Never start another return by going back and overwriting everything in the return you just filed. This will replace your info, which means you won't be able to retrieve your return later.
You might want to switch to the TurboTax CD/Download software to save money
If you still want to start another return in TurboTax Online, here’s what to do:
In accordance with IRS regulations, you can use the TurboTax software to e-file up to five (5) federal tax returns. You can prepare as many returns as you want, but only five can be e-filed.
For returns with multiple states, you can e-file up to three (3) states per federal return; the rest must be paper-filed (which probably isn't a big deal, as many nonresident state returns can't be e-filed anyway).
Our license agreement doesn't allow the use of TurboTax for commercial or professional tax preparation. If you need to e-file multiple returns and you are a professional tax preparer, take a look at our ProSeries or Lacerte software.